Category Display Name

[kbmets7]

Ok, here's what i am trying to do.

-I have my site with list of categories down left:
www.posterexpo.com

-I purchased magic SEO Urls, so a category's url looks like:
http://www.posterexpo.com/advertising-16/

-However I would like it to say:
http://www.posterexpo.com/advertising-posters-16/
adding the word "posters"

-But, I do not want to display the word posters for every category in the side box. It would look redundant.

So, is there a way to name a category "Advertising Posters, Sports Posters, Movie Posters, etc. But have it display something different.

I had a Yahoo store and this was easy to do, as there were two fields:
Category Name (this showed on the page)
Category Display Name (this showed in the url)

Thank you. and please help!